/Engine/Source/Runtime/SlateCore/Public/Rendering/SlateRenderer.h
Copies all slate windows out to a buffer at half resolution with debug information like the mouse cursor and any keypresses.
virtual void CopyWindowsToVirtualScreenBuffer ( const [TArray](API\Runtime\Core\Containers\TArray)< [FString](API\Runtime\Core\Containers\FString) > & KeypressBuffer )